I think that more often than not, it would end up wasting the fear enchantment. True, on those blows where paralyze doesn't trigger, you'd Fear them, but then you'd have to chase them down. Maybe worth playing around to see if it works better with both effects in one dagger, or as a paired set of artifacts, one with fear, and the other with paralyze.

Might be cool for RP purposes though? Could be that the blade is so evil that it scares people so much they actually can't move. Could also have it covered in poisons so it slowly kills them as well, or literally scares them to death. Could make it from an Orc dagger and call it the Goblin's Toothpick or something.

That'd totally work!

I once had a thief character use a version of the Fortify Restoration loop to enchant a simple silver ring with +60% Fortify Pickpocket and ~60 points of Unarmed damage. I called it "The Subtle Fist." Smithed the ring, too. Maxing out both crafting trees to make that legendary ring was probably one of my proudest moments in Skyrim. 

And centuries after the events of Skyrim, the Subtle Fist will be a much sought-after relic for thieves, treasure hunters and adventurers alike.

Damn straight!

I had posted a few in the past. Here they are:

Masseriel - Glass Sword crafted in Silent Moons camp when both moons were out and visible from near the forge, enchanted with Silent Moons Enchant and Frost Damage. This fragile looking sword created using ancient elven techniques from the finest Malachite gathered at the very top of the Throat of the World can cut through even the finest armor and chills the blood in enemy veins.

Secraen - Glass Dagger crafted in the same night, enchanted with Silent Moons Enchant and Paralyze. This deadly side weapon's razor-sharp edge can penetrate even the hardest materials and it's enchantment gives the wielder ability to direct strikes to the vital points of the enemy, paralyzing him and leaving to the mercy of the dagger's master.

Both of this weapons are infused with the power of the moons themselves and have slight glow in the night.

Edit: if you want to check out that thread for some other names, here it is 

Yeah, I played with Unofficial Patch